Restrictions for External Binding Customizations

There are several rules that apply to binding declarations made in an external binding customization file that do not apply to similar declarations made inline in a source schema:

• The binding customization file must begin with the jxb:bindings version attribute, plus attributes for the JAXB and XMLSchema namespaces:

  <jxb:bindings version="1.0" xmlns:jxb="http://java.sun.com/xml/ns/jaxb" 
  xmlns:xs="http://www.w3.org/2001/XMLSchema">

• The remote schema to which the binding declaration applies must be identified explicitly in XPath notation by means of a jxb:bindings declaration specifying schemaLocation and node attributes:

  • schemaLocation specifies a URI reference to the remote schema.

  • node specifies an XPath 1.0 expression that identifies the schema node within schemaLocation to which the given binding declaration is associated; in the case of the initial jxb:bindings declaration in the binding customization file, this node is typically "/xs:schema".

  Similarly, individual nodes within the schema to which customizations are to be applied must be specified using XPath notation; for example:

  <jxb:bindings node="//xs:complexType[@name=’USAddress’]">

  In such cases, the customization is applied to the node by the binding compiler as if the declaration was embedded inline in the node’s <xs:appinfo> element.

To summarize these rules, the external binding element <jxb:bindings> is only recognized for processing by a JAXB binding compiler in three cases:

• When its parent is an <xs:appinfo> element.

• When it is an ancestor of another <jxb:bindings> element.

• When it is the root element of a document. An XML document that has a <jxb:bindings> element as its root is referred to as an external binding declaration file.